The present invention relates to an electronic circuit for a quartz crystal timepiece provided with a stepping motor and comprising an oscillator followed by a divider feeding a logic stage for the control of the said motor.
It is known that one of the principal problems in electronic timepieces consists in finding a way to reduce the size of the electronic circuits. Now in a circuit, particularly if it relates to an integrated circuit the terminal connections take up a lot of room. It is thus important to be able to reduce their number.
This number is defined on the one hand by those of the external components which must be connected to the circuit and on the other hand by those of the controlling and actuating terminals. It could concern for example the control of the frequency of the quartz crystal and the actuating of the stopping of the timepiece when it is to be reset.
In a quartz crystal timepiece having digital display using a stepping motor, the integrated circuit used comprises two supply terminals, two terminals for the quartz crystal, two terminals for the motor and one terminal for controlling stopping of the timepiece. There is no terminal for the measurement of the frequency of the quartz crystal, as this can be effected on one of the terminals of the motor. There is in effect, at this point, the frequency derived by division of that of the quartz crystal.
The terminal to which the motor is connected thus fulfils two functions, that of controlling a motor and that of permitting the measurement of the frequency of the quartz crystal.